This application claims priority from the Netherlands application number 1019059 filed on Sep. 28, 2001, the contents of which are hereby incorporated by reference in their entirety.
1. Field of the Invention
The present invention relates to devices and methods for separating milk from dairy animals. In this context, separating is used to refer to accepting or rejecting, or sorting milk according to particular criteria.
2. Description of the Related Art
Such a device is known from EP-A-1000535. The device known therefrom is provided with a measuring device in the form of a color measuring system provided with one or more sensors comprising one or more sources irradiating the milk successively or simultaneously with radiation of one or more different wavelengths and/or different intensities, while, during at least a part of the time when the sources are in their switched-on position, one or more receivers establish the radiation intensity during a time interval. When the obtained measurement data indicate that the color of the measured milk deviates from normal values, the relevant milk is separated. However, it has appeared that the known device sometimes draws a wrong conclusion on the basis of the color measurements, so that e.g. suitable milk is not used for being processed further, but is discharged.
It is therefore desirable to provide an improved device for separating milk from a dairy animal by means of which the decision whether or not milk obtained is suitable for being processed further can be taken in an accurate manner.
According to the present invention, a device of the above-described type is provided for separating milk obtained from a dairy animal during a milking run. The device comprises a measuring device for measuring at least one milk variable during the course of the milking run of a dairy animal for obtaining a momentary measurement pattern of the milk variable and for issuing a signal indicative of the momentary measurement pattern. The device also includes a processing device for receiving the signal indicative of the momentary measurement pattern, the processing device comprising a memory for storing a reference measurement pattern for the milk variable and a comparing device for comparing the momentary measurement pattern of the milk variable with the reference measurement pattern and for issuing a comparison signal indicative of the comparison result.
By using not only a certain value, but the entire pattern i.e. course of the variable during the milking run for determining whether or not milk obtained should be processed further, it is possible to take a still more accurate decision whether or not the milk obtained should be processed further. Comparing measurement patterns with reference patterns appears to result in more correct decisions than exclusively comparing one single measured value.
In an embodiment of a device according to the, invention the processing device is provided with a memory for storing the measurement pattern respectively the reference measurement pattern.
The processing device is in particular provided with an averaging device for determining the average measurement pattern of a milk variable, it being advantageous that the memory is suitable for storing the average measurement pattern. Such an average measurement pattern is extremely useful for determining deviations from this average pattern, which may be an indication that the condition of the dairy animal is different from normal or that the milk produced by the dairy animal is different from normal. In other words the average measurement pattern constitutes the reference pattern. Such an average measurement pattern appears to provide per animal a more accurate indication of the deviation than a predetermined reference value. Especially when the average is a so-called progressive average, i.e. an average over e.g. the last ten milking runs (another number is possible as well), it is possible to make a correct decision.
Although for all the animals in a herd, the same thresholds may be used, it is advantageous that a memory of the processing device contains an upper threshold pattern and/or a lower threshold pattern for a relevant measurement pattern of a milk variable for each animal.
In a further embodiment of a device according to the invention, the device is provided with a milk line system comprising a number of lines and with at least one device controlled by the comparison signal for guiding milk flowing through the milk line system to a relevant line, it is possible to discharge automatically unsuitable milk or to convey suitable milk for being processed further.
For the purpose of enabling visual checking it is advantageous that the device comprises a displaying device for displaying the comparison signal. By providing the device with a device for generating a warning, said warning device being controlled by the comparison signal, it is possible, in certain situations, to give a warning to the manager of the device, e.g. in the form of a sound signal.
The measuring device preferably comprises a color sensor measuring system for measuring the intensity of at least one wavelength band, in particular in the visible wavelength range, of the milk obtained from the dairy animal, the variable being the intensity of the wavelength band. With the aid of the color sensor measuring system especially the intensity of the separate colors in the milk obtained from the separate udder quarters is established. Therefore, in this embodiment the variable is constituted by the color of the milk obtained.
In an embodiment of a device according to the invention the measuring device is constituted by a flow sensor for measuring the flow of the milk obtained during the milking run. The flow sensor preferably measures the flow of the milk obtained from the separate udder quarters.
In a further embodiment of a device according to the invention the measuring device is constituted by a conductivity meter known per se for measuring the conductivity of the milk obtained during the milking run. The conductivity meter preferably measures the conductivity of the milk obtained from the separate udder quarters.
In a still further embodiment of a device according to the invention the measuring device is constituted by a thermometer for measuring the temperature of the milk obtained during the milking run. The thermometer preferably measures the temperature of the milk obtained from the separate udder quarters.
In another further embodiment of a device according to the invention the measuring device is constituted by a component meter for measuring the quantity of a component of the milk obtained during the milking run, such as fat, protein, urea, bacteria, sugars, free fatty acids, germs, etc. The component meter preferably measures the components of the milk obtained from the separate udder quarters.
In a further embodiment of a device according to the invention the device is provided with a means for determining the period between two successive milking runs of the dairy animal, and the memory is suitable for containing a reference pattern depending on the measured period, respectively an upper threshold pattern and/or a lower threshold pattern depending on the measured period. This embodiment of the invention is based on the insight that the measured value of the variable depends on the measured period, also called interval, even when the condition of the dairy animal remains unchanged. By including, according to the invention, various reference values for the variable in the memory, the reference values depending on the measured period, a more accurate comparison of the measured values can take place, so that it is possible to take a correct decision whether or not the milk is suitable for being processed further. Moreover, after comparison of the measured values with the reference values, it is possible to draw more correct conclusions in relation to the condition respectively the health of the dairy animal. According to the invention, by period is meant in particular a period of time measured by a clock between two successive milking runs or a number of dairy animals milked between the two successive milking runs, said number being counted by a counter. Furthermore, another time-dependent variable may be measured as well, e.g. the total quantity of milk produced between the two successive milking runs.
The invention also includes a method for separating milk obtained from a dairy animal during a milking run. The method includes the steps of measuring a value of a variable in relation to the dairy animal during the entire course of the milking run, generating a momentary measurement pattern of the milk variable on the basis of the measured values, comparing the momentary measurement pattern with a reference measurement pattern for the milk variable, and separating milk based on the results of the comparison.